Hvac system air filter

ABSTRACT

An apparatus and a method are provided for a heating, ventilation, and air conditioning (HVAC) system air filter for a building ventilation system. The HVAC system air filter comprises a supportive frame configured to orient the HVAC system air filter within the building ventilation system. A composite filter medium retained within the supportive frame comprises a cotton gauze portion and an electrostatic portion. The cotton gauze portion is configured for treatment with a filter oil composition to enhance airflow and filtration of air flowing through the composite filter medium. The electrostatic portion is configured to electrostatically attract and agglomerate airborne molecular contaminants and volatile organic compounds (VOCs) as small as 0.001 microns in diameter. In some embodiments, the composite filter medium comprises substances configured to release a fragrance into air passing through the composite filter medium.

PRIORITY

This continuation application claims the benefit of and priority to U.S.patent application Ser. No. 16/514,954 filed and U.S. patent applicationSer. No. 14/974,092 filed on Dec. 18, 2015, now issued U.S. Pat. No.10,434,466 and U.S. patent application, entitled “Cabin Air Filter,”filed on Mar. 25, 2015 having application Ser. No. 14/668,772, nowissued U.S. Pat. No. 9,701,178.

FIELD

The field of the present disclosure generally relates to filter devices.More particularly, the field of the invention relates to an apparatusand a method for a HVAC system air filter to remove airborne molecularcontaminants and volatile organic compounds from air within interiorbuilding spaces.

BACKGROUND

Heating, ventilation, and air conditioning (HVAC) systems generallyoperate to provide optimal indoor air quality to occupants withininterior building spaces. HVAC systems achieve optimal indoor airquality by conditioning air, removing particle contaminants by way ofventilation and filtration of air, and providing proper buildingpressurization.

While there are many different HVAC system designs and operationalapproaches, and each building design is unique, HVAC systems generallyshare a few basic design elements. For example, outside air (“supplyair”) generally is drawn into a HVAC system of a building through an airintake. Once in the HVAC system, the supply air is filtered to removeparticle contaminants, then heated or cooled, and then circulatedthroughout the building by way of an air distribution system. Many airdistribution systems comprise a return air system configured to draw airfrom interior building spaces and return the air (“return air”) to theHVAC system. The return air is then mixed with supply air and thenfiltered, conditioned, and circulated throughout the building. Oftentimes, a portion of the air circulating within the building may beexhausted to the exterior of the building so as to maintain a desiredbarometric pressure within the building.

As will be appreciated, the effectiveness of the HVAC system to providedan optimal indoor air quality depends largely on an ability of an airfilter within the HVAC system to remove particle contaminants from theair within the building. A HVAC system air filter typically comprisesfibrous materials configured to remove solid particulates, such as dust,pollen, mold, and bacteria from the air passing through the HVAC system.A drawback to conventional HVAC system air filters, however, is thathighly effective air filters capable of removing very smallcontaminants, such as airborne molecular contaminants and volatileorganic compounds (VOCs), tend to restrict airflow through the airfilter, thereby making the HVAC system work harder and consume moreenergy.

Another drawback to conventional HVAC system air filters is that dirtyor clogged air filters typically are removed from the HVAC system anddiscarded, and a new HVAC system air filter is then installed. Further,HVAC system air filters may be unnecessarily discarded and replaced inan effort to increase HVAC system airflow and thus decrease operationcosts. Considering that there are millions of buildings with HVACsystems throughout the world, the volume of discarded air filters thatcould be eliminated from landfills is a staggering number. What isneeded, therefore, is a HVAC system air filter which may be periodicallycleaned and reused, and is configured for removing airborne molecularcontaminants and VOCs without obstructing air flow through HVAC systems.

SUMMARY

An apparatus and a method are provided for a heating, ventilation, andair conditioning (HVAC) system air filter for a building ventilationsystem. The HVAC system air filter comprises a supportive frameconfigured to suitably orient the HVAC system air filter within thebuilding ventilation system. In some embodiments, a filter mediumretained within the supportive frame comprises a cotton gauze portionand an electrostatic portion. The cotton gauze portion comprises atleast one layer of cotton gauze configured for treatment with a filteroil composition to enhance airflow and filtration of air flowing throughthe filter medium. In some embodiments, the filter oil compositioncomprises a first portion comprising paraffinic oil by volume of thecomposition, a second portion comprising polyalphaolefin (PAO) by volumeof the composition, and a third portion comprising red dye by volume ofthe composition. The electrostatic portion is configured toelectrostatically attract and agglomerate airborne molecularcontaminants and volatile organic compounds (VOCs) within air flowingthrough the building ventilation system. In some embodiments, apositively charged central screen and one or more layers of polarizablefibers entrap particle contaminants within the layers of polarizablefibers. In some embodiments, the electrostatic portion comprises atleast some fibers that are treated with a coating of positively chargedmolecules configured to electrostatically capture and destroy negativelycharged microbes and volatile organic compounds as small as 0.001microns in diameter. In some embodiments, the filter medium comprisessubstances configured to release a fragrance into air passing throughthe filter medium. The substances generally are located downstream ofthe electrostatic portion so as to avoid destruction of aromaticmolecules by the electrostatic portion.

In an exemplary embodiment, a heating, ventilation, and air conditioning(HVAC) system air filter to remove airborne molecular contaminants andvolatile organic compounds (VOCs) from air within building spaces,comprising: a supportive frame comprising a shape and size suitable fororienting the HVAC system air filter within a HVAC system of a building;and a filter medium retained within the supportive frame and configuredto remove the airborne molecular contaminants and volatile organiccompounds from air flowing through the HVAC system.

In another exemplary embodiment, the filter medium comprises a cottongauze portion comprising at least one layer of cotton gauze disposedbetween two epoxy-coated aluminum wire screens, the at least one layerof cotton gauze being suitable for treatment with a filter oilcomposition to cause tackiness of microscopic fiber strands comprisingthe filter medium. In another exemplary embodiment, the filter oilcomposition comprises a first portion comprising paraffinic oil byvolume of the composition, a second portion comprising polyalphaolefin(PAO) by volume of the composition, and a third portion comprising reddye by volume of the composition.

In another exemplary embodiment, an electrostatic portion of the filtermedium is configured to electrostatically attract and agglomerateparticle contaminants within the air flowing through the HVAC system. Inanother exemplary embodiment, the electrostatic portion of the filtermedium comprises a central screen configured to be electrically charged,the central screen being covered on each side by at least one layer offibers capable of being electrically polarized, each of the at least onelayer of fibers being covered by a grounded wire screen, wherein uponpositively charging the central screen the at least one layer of fiberspolarizes particle contaminants within the air flowing through the HVACsystem, thereby causing the contaminants to be electrostaticallyentrapped within the at least one layer of fibers. In another exemplaryembodiment, the electrostatic portion of the filter medium comprises atleast some fibers that are treated with a coating of antimicrobialmolecules configured to destroy microbes, the antimicrobial moleculescomprising positively charged molecules distributed around the entirecircumference of each of the at least some fibers and configured tocooperate with polarized fibers within the filter medium. In anotherexemplary embodiment, the positively charged molecules are configured toelectrostatically capture negatively charged microbes and volatileorganic compounds as small as substantially 0.001 microns in diameterwithin the air flowing through the HVAC system. In another exemplaryembodiment, the filter medium is configured to electrostatically entrapparticle contaminants and release a fragrance into the air flowingthrough the ventilation system, the filter medium comprisingantimicrobial molecules configured to destroy entrapped particlecontaminants, the filter medium comprising at least one substanceconfigured to release the fragrance into air passing through the filtermedium, wherein the at least one substance is located downstream of theantimicrobial molecules so as to avoid destruction of aromatic moleculesby the antimicrobial molecules.

In an exemplary embodiment, a heating, ventilation, and air conditioning(HVAC) system air filter for a building ventilation system, comprising:a supportive frame configured to suitably orient the HVAC system airfilter within the building ventilation system; and a composite filtermedium comprising a cotton gauze portion and an electrostatic portionconfigured to electrostatically attract and agglomerate airbornemolecular contaminants and volatile organic compounds (VOCs) within airflowing through the building ventilation system, the composite filtermedium being retained within the supportive frame.

In another exemplary embodiment, the electrostatic portion comprises apositively charged central screen, the central screen being covered oneach side by at least one layer of polarized fibers, each of the atleast one layer of polarized fibers being covered by a grounded wirescreen, wherein the positively charged central screen and the at leastone layer of fibers polarizes particle contaminants within the airflowing through the building ventilation system, thereby entrapping theparticle contaminants within the at least one layer of polarizablefibers. In another exemplary embodiment, the electrostatic portioncomprises at least some fibers that are treated with a coating ofpositively charged molecules configured to electrostatically capture anddestroy negatively charged microbes and volatile organic compounds assmall as substantially 0.001 microns in diameter within the air flowingthrough the building ventilation system.

In another exemplary embodiment, the composite filter medium comprisesat least one substance configured to release a fragrance into airpassing through the composite filter medium, wherein the at least onesubstance is located downstream of the electrostatic portion so as toavoid destruction of aromatic molecules by the electrostatic portion. Inanother exemplary embodiment, the cotton gauze portion comprises atleast one layer of cotton gauze configured for treatment with a filteroil composition to enhance airflow and filtration of air flowing throughmicroscopic fiber strands comprising the composite filter medium. Inanother exemplary embodiment, the filter oil composition comprises afirst portion comprising paraffinic oil by volume of the composition, asecond portion comprising polyalphaolefin (PAO) by volume of thecomposition, and a third portion comprising red dye by volume of thecomposition.

In an exemplary embodiment, a method for cleaning a heating,ventilation, and air conditioning (HVAC) system air filter which isinstalled within a HVAC system of a building, the method comprising:removing the HVAC system air filter from the HVAC system; clearing theHVAC system of any debris trapped therein; flushing contaminants from afilter medium of the HVAC air filter by way of a water hose; allowingthe water and contaminants to drain from the filter medium; and allowingthe filter medium to dry.

In another exemplary embodiment, the filter medium comprises a cottongauze portion comprising at least one layer of cotton gauze configuredfor treatment with a filter oil composition comprising a first portioncomprising paraffinic oil by volume of the composition, a second portioncomprising polyalphaolefin (PAO) by volume of the composition, and athird portion comprising red dye by volume of the composition. Inanother exemplary embodiment, flushing contaminants from the filtermedium further comprises using a solvent to remove a filter oilcomposition from a cotton gauze portion of the filter medium. In anotherexemplary embodiment, allowing the filter medium to dry furthercomprises uniformly applying a filter oil composition to a cotton gauzeportion of the filter medium and allowing the filter oil composition towick into the cotton gauze portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings refer to embodiments of the present disclosure in which:

FIG. 1 illustrates a cross-sectional view of an exemplary useenvironment wherein a HVAC system air filter is incorporated into a HVACsystem of a building, according to the present disclosure;

FIG. 2 illustrates a schematic view of an exemplary embodiment of a HVACsystem comprising a HVAC system air filter in accordance with thepresent disclosure;

FIG. 3 illustrates an exemplary embodiment of a HVAC system air filter,according to the present disclosure;

FIG. 4 illustrates an exemplary embodiment of a HVAC system air filterin accordance with the present disclosure;

FIG. 5 illustrates a cross-sectional view of an exemplary embodiment ofa portion of a composite filter medium configured for entrappingparticle contaminants by way of electrostatic attraction andagglomeration;

FIG. 6 illustrates cross-sectional views of an exemplary embodiment of apolarized fiber and an unpolarized passive fiber being exposed toparticle contaminants within an air stream flowing from an upstream areato a downstream area; and

FIG. 7 illustrates a graph showing an experimentally determinedrelationship between fine dust loading and a drop in pressure acrosseach of several air filter devices.

While the present disclosure is subject to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and will herein be described in detail. Theinvention should be understood to not be limited to the particular formsdisclosed, but on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the present disclosure.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present disclosure. Itwill be apparent, however, to one of ordinary skill in the art that theinvention disclosed herein may be practiced without these specificdetails. In other instances, specific numeric references such as “firstportion,” may be made. However, the specific numeric reference shouldnot be interpreted as a literal sequential order but rather interpretedthat the “first portion” is different than a “second portion.” Thus, thespecific details set forth are merely exemplary. The specific detailsmay be varied from and still be contemplated to be within the spirit andscope of the present disclosure. The term “coupled” is defined asmeaning connected either directly to the component or indirectly to thecomponent through another component. Further, as used herein, the terms“about,” “approximately,” or “substantially” for any numerical values orranges indicate a suitable dimensional tolerance that allows the part orcollection of components to function for its intended purpose asdescribed herein.

In general, the present disclosure describes an apparatus and a methodfor a heating, ventilation, and air conditioning (HVAC) system airfilter to remove airborne molecular contaminants and volatile organiccompounds (VOCs) from air within interior building spaces. The HVACsystem air filter comprises a supportive frame having a shape and sizesuitable for orienting the HVAC system air filter within a HVAC systemof a building. A filter medium retained within the supportive frame isconfigured to remove the airborne molecular contaminants and volatileorganic compounds from air flowing through the HVAC system. The filtermedium comprises a cotton gauze portion which includes one or morelayers of cotton gauze disposed between two epoxy-coated aluminum wirescreens. The layers of cotton gauze are suitable for treatment with afilter oil composition to cause tackiness of microscopic fiber strandscomprising the filter medium. The filter oil composition preferablycomprises a first portion comprising paraffinic oil by volume of thecomposition, a second portion comprising polyalphaolefin (PAO) by volumeof the composition, and a third portion comprising red dye by volume ofthe composition. An electrostatic portion of the filter medium isconfigured to electrostatically attract and agglomerate particlecontaminants within the air flowing through the HVAC system. In someembodiments, the electrostatic portion of the filter medium comprises acentral screen configured to be electrically charged. The central screenis covered on each side by at least one layer of fibers capable of beingelectrically polarized. An exterior grounded wire screen covers thelayers of polarizable fibers such that the layers of polarizable fibersare disposed between the central screen and the ground wire screen. Uponpositively charging the central screen, the layers of fibers polarizeparticle contaminants within the air flowing through the HVAC system,thereby causing the contaminants to be electrostatically entrappedwithin the layers of polarizable fibers. In some embodiments, theelectrostatic portion comprises at least some fibers that are coatedwith positively charged antimicrobial molecules configured to destroymicrobes. The positively charged molecules are configured toelectrostatically capture negatively charged microbes and volatileorganic compounds as small as substantially 0.001 microns in diameterwithin the air flowing through the HVAC system. In some embodiments, thefilter medium further comprises at least one substance configured torelease a fragrance into the air flowing through the buildingventilation system. The substance preferably is located downstream ofthe electrostatic portion and the antimicrobial molecules so as to avoiddestruction of aromatic molecules by the antimicrobial molecules.

FIG. 1 illustrates an exemplary use environment 100 wherein a HVACsystem air filter 104 is incorporated into a HVAC system 108 of abuilding 112 so as to clean an air stream drawn through the air filter104. After passing through the HVAC system air filter 104, the airstream is routed into one or more building spaces 116 by way of a supplyductwork 110. Air within the building spaces 116 is routed back to theHVAC system 108 by way of a return ductwork 114. It will be appreciatedthat the building 112 may comprise multiple stories, each of whichstores including one or more building spaces 116, as illustrated in FIG.1, or may comprise a single story building, including but not limited toa detached residential home.

As shown in FIG. 2, the HVAC system 108 generally comprises a fan 120configured to draw a return air stream 124 from the building spaces 116through the HVAC system air filter 104 whereby airborne molecularcontaminants, volatile organic compounds, and other particlecontaminants are removed from the air stream. Particle contaminantsremoved from the return air stream 124 are entrapped in the HVAC systemair filter 104. The fan 120 then pushes a clean air stream 128 throughan air conditioning system 132 and a heater core 136 and then into thebuilding spaces 116. As will be appreciated, the air conditioning system132 and the heater core 136 facilitate providing a consistent,comfortable temperature within the building spaces 116 by respectivelycooling and heating the clean air stream 128, as needed. As furthershown in FIG. 2, the return air stream 124 may be combined with anoutside air stream 126, as well as with a bypass air stream 130 airstream so as to maintain a desired barometric pressure within the HVACsystem 108 and within the building spaces 116. In some embodiments, anexhaust air stream 134 may be further incorporated into the HVAC system108 so as to maintain the desired barometric pressure and to allow entryof the outside air stream 126.

FIG. 3 illustrates an exemplary embodiment 140 of a HVAC system airfilter 104 according to the present disclosure. The HVAC system airfilter 104 generally comprises a filter medium 144 within a supportiveframe 148. The supportive frame 148 is configured to orient the HVACsystem air filter 104 within the HVAC system 108 such that the returnair stream 124 is directed through the filter medium 144. As such, thesupportive frame 148 comprises a shape and size suitable for supportingthe HVAC system air filter 104 within the HVAC system 108. It will beappreciated that the shape and size of the supportive frame 148 willvary depending upon a make and model of the HVAC system 108 for whichthe air filter 104 is intended to be used.

The supportive frame 148 may comprise various fastening, or supportive,structures and materials suitably configured for securing the HVACsystem air filter 104 within a particular HVAC system 108. To this end,in the embodiment illustrated in FIG. 3, the supportive frame 148comprises a grate 152 configured to support the filter medium 144 withinthe HVAC system 108. In another exemplary embodiment 156, illustrated inFIG. 4, the supportive frame 148 comprises rigid end supports 160 andrecesses 164 configured to orient the HVAC system air filter 104 withina particular make and model of HVAC system 108. As will be recognized,the supportive frame 148 illustrated in FIG. 4 has a very differentshape than the shape of the supportive frame illustrated in FIG. 3. Itshould be understood, therefore, that the various structures, shapes,and materials incorporated into the supportive frame 148, and thus theHVAC system air filter 104 as a whole, will vary depending upon theparticular HVAC system 108 for which the HVAC system air filter 104 isintended to be used without detracting from the spirit and scope of thepresent disclosure.

It will be appreciated that the filter medium 144 generally is retainedwithin the supportive frame 148. It is contemplated that any of avariety of fasteners or structures may be implemented so as to retainthe filter medium 144 within the supportive frame 148. In someembodiments, such as the embodiment of FIG. 3, the supportive frame 148comprises the grate 152, or similar structure, which encloses the filtermedium 144 within the supportive frame 148 without restricting airflowthrough the filter medium 144. In some embodiments, the supportive frame148 comprises various structures, such as the rigid end supports 160shown in FIG. 4, which are configured to retain and orient the filtermedium 144 within the supportive frame 148. In some embodiments, thesupportive frame 148 is molded directly onto the edges of the filtermedium 144, thereby retaining the filter medium within the frame. Insome embodiments, the supportive frame 148 may be molded to wiresupports of the filter medium 144. For example, in some embodiments, thefilter medium 144 is disposed between a first metal screen and a secondmetal screen, and the supportive frame 148 is molded onto the first andsecond metal screens so as to retain the filter medium 144 within thesupportive frame. In some embodiments, the supportive frame 148 maycomprise a crimped portion that folds onto and retains the metal screensand the filter medium 144 within the supportive frame. It will beappreciated that by those skilled in the art that fastening the filtermedium 144 to the supportive frame 148 renders the filter medium 144irremovable from the supportive frame 148. In some embodiments, however,the filter medium 144 may be removable from the supportive frame 148without deviating from the scope of the present disclosure.

It is contemplated that a user of the HVAC system air filter 104 mayperiodically clean the filter medium 144 rather than replacing the HVACsystem air filter 104, as is typically done with conventional air filtersystems. It is envisioned that the HVAC system air filter 104 may beremoved from the HVAC system 108, any trapped debris is then removedfrom the HVAC system 108, and then a water hose is used to flushcontaminants from the filter medium 144, thereby leaving the filterclean and ready for reuse. In some embodiments, wherein the filtermedium 144 comprises a filter oil composition, a solvent may be used toremove the filter oil from the filter medium 144. Once the filter medium144 is completely dry, a suitably formulated filter oil composition maybe uniformly applied and allowed to wick into the filter medium 144 andthen the HVAC system air filter 104 may be reinstalled into the HVACsystem 108. Various other cleaning methods will be apparent to thoseskilled in the art without deviating from the spirit and scope of thepresent disclosure.

The filter medium 144 preferably comprises at least a cotton gauzeportion including 4 to 6 layers of cotton gauze sandwiched between twoepoxy-coated aluminum wire screens. The cotton is advantageously treatedwith the above-mentioned suitably formulated filter oil composition forcausing tackiness throughout microscopic strands comprising the filtermedium 144. The nature of the cotton allows high volumes of airflow, andwhen combined with the tackiness of the filter oil composition creates apowerful filtering medium which ensures a high degree of air filtration.

During operation of the HVAC system 108, contaminant particles cling tothe fibers within the volume of the filter medium 144 and become part ofthe filtering medium 144, a process referred to as “depth loading.” Itwill be appreciated that depth loading allows the HVAC system air filter104 to capture and retain significantly more contaminants per unit ofarea than conventional air filters. Contaminants collected on thesurface of the HVAC system air filter 104 have little effect on air flowduring much of the filter's service life because there are no smallholes for the contaminants to clog. Contaminant particles are stopped bythe layers of cotton gauze and held in suspension by the filter oilcomposition. Moreover, as the HVAC system air filter 104 collects anincreasing volume of contaminants and debris, an additional form offiltering action begins to take place as the return air stream 124 firstpasses through the trapped contaminants on the surface of the filtermedium 144 before passing through deeper layers within the filter medium144. In essence, the trapped contaminants begin to operate as a filtermaterial which precedes the filter medium 144. Thus, the HVAC system airfilter 104 continues to exhibit a high degree of air flow and filtrationthroughout the service life of the filter, thereby reducing operatingcosts of the HVAC system 108.

As will be appreciated, treating the filter medium 144 with the filteroil composition generally enables the filter medium 144 to capturecontaminants by way of interception, whereby contaminants, such as byway of non-limiting example, dirt particles, traveling with the returnair stream 124 directly contact the fibers comprising the filter medium144 and are then held in place by the filter oil composition. Larger orheavier particles are generally captured by way of impaction, wherebythe inertia or momentum of the particles causes them to deviate from thepath of the return air stream 124 through the filter medium 144, andinstead the particles run straight into the fibers and are captured bythe filter oil composition.

Particle contaminants having very small sizes may be captured by way ofdiffusion. As will be appreciated, small particles are highly affectedby forces within the return air stream 124 through the filter medium144. Forces due to velocity changes, pressure changes, and turbulencecaused by other particles, as well as interaction with air molecules,generally causes the small particles to follow random, chaotic flowpaths through the filter medium 144. Consequently, the small particlesdo not follow the return air stream 124, and their erratic motion causesthem to collide with the fibers comprising the filter medium 144 andremain captured by the filter oil composition. Diffusion and the filteroil composition enable the HVAC system air filter 104 to captureparticle contaminants having sizes that are much smaller than theopenings between the fibers comprising the filter medium 144.Furthermore, the filter oil composition enables the HVAC system airfilter 104 to capture contaminants throughout the volume of the filtermedium 144, rather than only on the surface of the filter as is commonwith conventional air filters. The multiple layers of cotton fiberscomprising the filter medium 144 coupled with the tackiness provided bythe filter oil composition provide many levels of contaminant retention,thereby enabling the HVAC system air filter 104 to hold significantlymore contaminants per unit of area of the filter medium 144 than ispossible with conventional air filters.

As will be appreciated, the filter oil composition of the presentdisclosure is critical to the enhanced air flow and filtrationproperties of the HVAC system air filter 104. In some embodiments, thefilter oil composition comprises an oil formulation which isnon-reactive, has an excellent oxidation stability, possesses goodthermal stability, and retains suitable viscosity at normal operatingtemperatures of the HVAC system 108. In some embodiments, the filter oilcomposition may be a mixture of oils and dyes (to provide color)suitable for enhancing the tackiness of the filter medium 144, such asby way of non-limiting example, paraffinic oils, polyalphaolefins, andthe like. In some embodiments, the filter oil composition comprises amixture of 96.74% paraffinic oil by volume, 3.20% polyalphaolefin (PAO)by volume, and 0.06% red dye by volume. In some embodiments, the filteroil composition has a viscosity at 100 degrees-C. ranging betweensubstantially 7.2 and 7.6 centistokes (cSTs). It is to be understoodthat the particular oils and dyes, as well as their colors orviscosities, and their individual concentrations within the filter oilcomposition may be altered without deviating from the spirit and thescope of the present disclosure.

In some embodiments, the layers of cotton gauze treated with the filteroil composition are coupled with portions of the filter medium 144wherein other filtration mechanisms are used, thereby forming acomposite filter medium 144 capable of removing airborne molecularcontaminants and volatile organic compounds from the return air stream124. In some embodiments, the composite filter medium 144 comprises acotton gauze portion, as described herein, and an electrostatic portion.FIG. 5 illustrates a cross-sectional view of an electrostatic portion168 of the composite filter medium 144 which is downstream of the cottongauze layers and configured for utilizing electrostatic attraction andagglomeration to entrap particle contaminants. The embodiment of FIG. 5is configured to entrap contaminant particles possessing diameters onthe order of substantially 0.3 microns. The electrostatic portion 168 ofthe composite filter medium 144 comprises a central screen 172configured to be electrically charged to a high electrostatic potential.In some embodiments, the central screen 172 is positively charged tosubstantially 7,000 VDC. The central screen 172 is covered on each sideby at least one layer of fibers 176 capable of being electricallypolarized. As shown in FIG. 5, each of the at least one layer ofpolarizable fibers 176 is covered by an exterior grounded wire screen180. It will be appreciated that upon positively charging the centralscreen 172, the polarizable fibers 176 operate to polarize incomingparticle contaminants within the return air stream 124, thereby causingthe contaminants to become electrostatically attracted to thepolarizable fibers 176. Thus, particle contaminants that would otherwiseavoid directly colliding with the fibers 176 are electrostaticallycaptured and entrapped within the filter medium 144.

FIG. 6 illustrates cross-sectional views of a polarized fiber 184 and anunpolarized passive fiber 188 being exposed to particle contaminantswithin an air stream 192 that flows from an upstream area 196 to adownstream area 200. As shown in FIG. 6, electrostatic attractionbetween the particle contaminants and the polarized fiber 184 uniformlydistributes the contaminants on the surface of the polarized fiber 184.The electrostatic attraction ensures the capture of contaminants thatwould otherwise pass by the fiber 184 without a direct collision andcontinue flowing to the downstream area 200. Unlike the polarized fiber184, the unpolarized passive fiber 188 relies upon direct collisionsbetween the particle contaminants and the fiber, thus allowingnon-colliding contaminants to continue flowing to the downstream area200.

As further illustrated in FIG. 6, the contaminants that collide with thepassive fiber 188 tend to accumulate on an upstream side of the passivefiber 188. It will be appreciated that as the accumulation ofcontaminants on the upstream side of the passive fiber 188 grows, theair stream 192 becomes proportionally restricted. Thus, filter mediums144 comprising unpolarized passive fibers 188 are prone to clogging andgreater loading than generally occurs with filter mediums 144 comprisingpolarized fibers 184. FIG. 7 illustrates a graph 204 showing anexperimentally determined relationship between fine dust loading and aconsequent drop in pressure across each of several air filter devices.FIG. 7 clearly demonstrates that filter media 144 comprising polarizedfibers 184 entrap more contaminants with a lower pressure drop acrossthe filter than is otherwise possible with conventional filter mediacomprising unpolarized passive fibers 188.

In some embodiments, at least some of the fibers comprising thecomposite filter medium 144 are treated with a coating of antimicrobialmolecules configured to destroy microbes on contact. Preferably, thecoating of antimicrobial molecules surrounds the entire circumference ofeach fiber strand that is treated. In some embodiments, theantimicrobial molecules comprise positively charged molecules that areconfigured to cooperate with the polarized fibers 176 of the compositefilter medium 144. It is contemplated that since many microbes andvolatile organic compounds are negatively charged, incorporating theantimicrobial molecules into the composite filter medium 144 willelectrostatically capture the particle contaminants, thereby enablingthe HVAC system air filter 104 to remove particles from the return airstream 124 as small as 0.001 microns in diameter, or smaller, such asmany odors, irritants, toxic compounds, and the like.

In some embodiments, the fibrous materials comprising a portion of thecomposite filter medium 144 may comprise at least one substanceconfigured to release a fragrance into air passing through the compositefilter medium. Thus, in some embodiments, the HVAC system air filter 104is configured to introduce a desired aroma into the building spaces 116.It is contemplated that various HVAC system air filters 104 may comprisedifferent fragrances, thereby enabling a user to select an air filter104 according to a desired aroma. In some embodiments, a particularscent or aroma may be distributed through the HVAC system 108 into thebuilding spaces 116 so as to provide an aroma therapy by way of the HVACsystem air filter 104.

In some embodiments, the substances configured to release a fragranceare incorporated into the composite filter medium 144 comprising theantimicrobial molecules. Thus, in some embodiments, the composite filtermedium 144 utilizes treated cotton gauze and electrostatic attraction toentrap particle contaminants while simultaneously releasing an aromainto the building spaces 116. It will be appreciated, however, that thesubstances for releasing a fragrance preferably are located within thecomposite filter medium 144 downstream of the antimicrobial molecules soas to avoid destruction of aromatic molecules by the antimicrobialmolecules.

It is contemplated that the fragrance may be any natural substance,synthetic material, (incorporating aldehydes, ketones, esters, and otherchemical constituents), or combinations thereof which is known in theart and suitable for use in candles for imparting an odor, aroma, orfragrance. In some embodiments, suitable natural and syntheticfragrance/flavor substances may include those compiled by the U.S. Foodand Drug Administration in Title 21 of the Code of Federal Regulations,Sections 172.510 and 172.515 respectively. In some embodiments, suitablefragrances may comprise spice oil, flower oil, fruit oil, and the like.In some embodiments, suitable fragrances may comprise fragrancecomponents, such as for example benzaldehydes, phenols, cinnamicaldehydes and esters, octadienes, dienes, cyclohexadienes, terpenes, andthe like. Further details regarding dispersion of aromas by way of airfilters and fragrance compositions are disclosed in U.S. patentapplication Ser. No. 10/544,157, entitled “Vehicle cabin air filterfreshener,” filed on Aug. 13, 2003, the entirety of each of which isincorporated herein by reference.

It should be understood that the HVAC system air filter 104 is notlimited solely to treating air within buildings and detached residentialhomes, but rather may be used for vehicle passenger cabins whereinpassengers, drivers, as well as occupants reside, such as by way ofnon-limiting example, automobiles, trucks, recreational vehicles, buses,earthmoving equipment and tractors with enclosed cabins, crane operatorcabins, various cargo moving vehicles, locomotives, rail passenger cars,airplanes, helicopters, ship cabins, airship cabins, and the like.Moreover, the HVAC system air filter 104 may be incorporated into HVACsystems other than as illustrated in FIG. 1, such as by way ofnon-limiting example, central HVAC systems, rooftop HVAC systems,wall-mounted HVAC systems, as well as portable HVAC systems, and thelike.

While the invention has been described in terms of particular variationsand illustrative figures, those of ordinary skill in the art willrecognize that the invention is not limited to the variations or figuresdescribed. In addition, where methods and steps described above indicatecertain events occurring in certain order, those of ordinary skill inthe art will recognize that the ordering of certain steps may bemodified and that such modifications are in accordance with thevariations of the invention. Additionally, certain of the steps may beperformed concurrently in a parallel process when possible, as well asperformed sequentially as described above. To the extent there arevariations of the invention, which are within the spirit of thedisclosure or equivalent to the inventions found in the claims, it isthe intent that this patent will cover those variations as well.Therefore, the present disclosure is to be understood as not limited bythe specific embodiments described herein, but only by scope of theappended claims.

What is claimed is:
 1. A heating, ventilation, and air conditioning(HVAC) system air filter to remove airborne molecular contaminants andvolatile organic compounds (VOCs) from air within building spaces,comprising: a supportive frame comprising a shape and size suitable fororienting the HVAC system air filter within a HVAC system of a building;and a filter medium retained within the supportive frame and configuredto remove the airborne molecular contaminants and volatile organiccompounds from air flowing through the HVAC system.
 2. The HVAC systemair filter of claim 1, wherein the filter medium comprises a cottongauze portion comprising at least one layer of cotton gauze disposedbetween two epoxy-coated aluminum wire screens, the at least one layerof cotton gauze being suitable for treatment with a filter oilcomposition to cause tackiness of microscopic fiber strands comprisingthe filter medium.
 3. The HVAC system air filter of claim 2, wherein thefilter oil composition comprises a first portion comprising paraffinicoil by volume of the composition, a second portion comprisingpolyalphaolefin (PAO) by volume of the composition, and a third portioncomprising red dye by volume of the composition.
 4. The HVAC system airfilter of claim 1, wherein an electrostatic portion of the filter mediumis configured to electrostatically attract and agglomerate particlecontaminants within the air flowing through the HVAC system.
 5. The HVACsystem air filter of claim 4, wherein the electrostatic portion of thefilter medium comprises a central screen configured to be electricallycharged, the central screen being covered on each side by at least onelayer of fibers capable of being electrically polarized, each of the atleast one layer of fibers being covered by a grounded wire screen,wherein upon positively charging the central screen the at least onelayer of fibers polarizes particle contaminants within the air flowingthrough the HVAC system, thereby causing the contaminants to beelectrostatically entrapped within the at least one layer of fibers. 6.The HVAC system air filter of claim 4, wherein the electrostatic portionof the filter medium comprises at least some fibers that are treatedwith a coating of antimicrobial molecules configured to destroymicrobes, the antimicrobial molecules comprising positively chargedmolecules distributed around the entire circumference of each of the atleast some fibers and configured to cooperate with polarized fiberswithin the filter medium.
 7. The HVAC system air filter of claim 6,wherein the positively charged molecules are configured toelectrostatically capture negatively charged microbes and volatileorganic compounds as small as substantially 0.001 microns in diameterwithin the air flowing through the HVAC system.
 8. The HVAC system airfilter of claim 4, wherein the filter medium is configured toelectrostatically entrap particle contaminants and release a fragranceinto the air flowing through the ventilation system, the filter mediumcomprising antimicrobial molecules configured to destroy entrappedparticle contaminants, the filter medium comprising at least onesubstance configured to release the fragrance into air passing throughthe filter medium, wherein the at least one substance is locateddownstream of the antimicrobial molecules so as to avoid destruction ofaromatic molecules by the antimicrobial molecules.
 9. A heating,ventilation, and air conditioning (HVAC) system air filter for abuilding ventilation system, comprising: a supportive frame configuredto suitably orient the HVAC system air filter within the buildingventilation system; and a composite filter medium comprising a cottongauze portion and an electrostatic portion configured toelectrostatically attract and agglomerate airborne molecularcontaminants and volatile organic compounds (VOCs) within air flowingthrough the building ventilation system, the composite filter mediumbeing retained within the supportive frame.
 10. The HVAC system airfilter of claim 9, wherein the electrostatic portion comprises apositively charged central screen, the central screen being covered oneach side by at least one layer of polarized fibers, each of the atleast one layer of polarized fibers being covered by a grounded wirescreen, wherein the positively charged central screen and the at leastone layer of fibers polarizes particle contaminants within the airflowing through the building ventilation system, thereby entrapping theparticle contaminants within the at least one layer of polarizablefibers.
 11. The HVAC system air filter of claim 10, wherein theelectrostatic portion comprises at least some fibers that are treatedwith a coating of positively charged molecules configured toelectrostatically capture and destroy negatively charged microbes andvolatile organic compounds as small as substantially 0.001 microns indiameter within the air flowing through the building ventilation system.12. The HVAC system air filter of claim 9, wherein the composite filtermedium comprises at least one substance configured to release afragrance into air passing through the composite filter medium, whereinthe at least one substance is located downstream of the electrostaticportion so as to avoid destruction of aromatic molecules by theelectrostatic portion.
 13. The HVAC system air filter of claim 9,wherein the cotton gauze portion comprises at least one layer of cottongauze configured for treatment with a filter oil composition to enhanceairflow and filtration of air flowing through microscopic fiber strandscomprising the composite filter medium.
 14. The HVAC system air filterof claim 13, wherein the filter oil composition comprises a firstportion comprising paraffinic oil by volume of the composition, a secondportion comprising polyalphaolefin (PAO) by volume of the composition,and a third portion comprising red dye by volume of the composition. 15.A method for cleaning a heating, ventilation, and air conditioning(HVAC) system air filter which is installed within a HVAC system of abuilding, the method comprising: removing the HVAC system air filterfrom the HVAC system; clearing the HVAC system of any debris trappedtherein; flushing contaminants from a filter medium of the HVAC airfilter by way of a water hose; allowing the water and contaminants todrain from the filter medium; and allowing the filter medium to dry. 16.The method of claim 15, wherein the filter medium comprises a cottongauze portion comprising at least one layer of cotton gauze configuredfor treatment with a filter oil composition comprising a first portioncomprising paraffinic oil by volume of the composition, a second portioncomprising polyalphaolefin (PAO) by volume of the composition, and athird portion comprising red dye by volume of the composition.
 17. Themethod of claim 15, wherein flushing contaminants from the filter mediumfurther comprises using a solvent to remove a filter oil compositionfrom a cotton gauze portion of the filter medium.
 18. The method ofclaim 15, wherein allowing the filter medium to dry further comprisesuniformly applying a filter oil composition to a cotton gauze portion ofthe filter medium and allowing the filter oil composition to wick intothe cotton gauze portion.